Apple has followed through with plans to stop selling Fitbit devices. As noted by MacRumors, the company has pulled all Fitbit products from its online store and has begun removing them from the shelves of its retail stores as well.

Previously, Apple carried the Fitbit Flex fitness band and the classic Fitbit one, both of which connected to iOS devices. The reason behind the removals is unknown, but there does appear to be tension brewing between the two firms.

In October, Fitbit confirmed that it had no plans to support HealthKit, Apple’s new health data aggregation platform. As the number one fitness tracker maker in the world, Fitbit’s announcement likely made significant waves for Apple.

Additionally, Fitbit recently announced a handful of new products, including the Surge smartwatch, which encroaches further on Apple Watch territory. It’s possible (though seemingly unlikely) that Apple dropped Fitbit for competitive reasons.

This isn’t the first time we’ve heard of Apple removing products in recent weeks—last month, Apple pulled Bose audio products from its stores. Interestingly enough, it’s still offering other brands of headphones and fitness trackers, for now.